I don't believe you can get Keldeo on the pokewalker because the pokewalker is for Heartgold and Soulsilver which is only the Kanto-Johto reigon (Mostly johto.).
At the time Heartgold and SoulSilver was released in 2010, very few even heard of black and white, and none of keldeo.
Basically, you DON'T get it on the pokewalker, it isn't possible to get keldeo at all unless you can somehow trade from a black and white 2 from Japan which is very unlikely.
Yes, Keldeo is a legendary Pokemon.
you don't catch Keldeo, you have to get him as an event. :(
Here's some codes I found for Keldeo. Ordinary Forme Keldeo skin: KELDEOCGEARBW Resolute Forme Keldeo skin: KELDEOCGEARBW2
keldeo has yet to be released on the Internet/wi-fi. but there are some clues that there is going to be a keldeo event. be patient.
Keldeo Resolute Form in Pokemon is when Keldeo has the secret sword. This is an evolution from standard form.
there is 2 forms of keldeo
Keldeo is a real pokemon. Incidentally, keldeo was introduced in Pokemon Black and White.
you can get keldeo by pokecheck
Keldeo is a Water and Fighting type pokemon.
Keldeo is obtained only through an event
You cannot get the Professor in his lab in order to get Keldeo, Keldeo can only be acquired via trades or through a special event.
U go suck a ballsack and win a free keldeo